Apparatus for converting analog quantities into numerical quantities



June 6, 1967 w. BARwscz Ems.. 3,324,345

APPARATUS FOR CONVERTING ANALOG QUANTITIES INTO NUMERICAL QUANTITIESW/ESLAW BARW/CZ JAN LEWKO `Jilin@ 6, 1967 w. BAwacz ETAL 3,324,345

APPARATUS FOR CONVERTING ANALOG QUANTITIES INTO NUMERICAL QUANTITIESFiled Aug. 19, 1963 l 3 Sheets-Sheet 2 INVENTORS W/ES LA W HAR W/CZ June6, 1967 APPARATUS FOR CONVERTING ANALOG QUANTITIES w. BARWscz ETAL3,324,345

INTO NUMERICAL QUANTITIES v Filed Aug. 19, 1963 3 Sheets-Sheet 3 221| lf24 25 l i AMP. l l l l F .NG

,YSTEM f,2l SYSTEM SYSTEM GENERAT'ING GENERATING VOLTAGE VOLTAGE mm MJAN LE WKO P: E L

United States Patent O 3,324,345 APPARATUS FOR CONVERTING ANALGG QUAN-TITIES INTO NUMERICAL QUANTITIES Wieslaw Barwicz, ul, Zawiszy 40 m. 68,and Jan Lewlto ul. Brzozowa 3 m. 5, both of Warsaw, Poland p Filed Aug.19, 1963, Ser. No. 303,076 Claims priority, application Poland, Aug. 21,1962, P 99,534 Claims. (Cl. S15-8.5)

This invention relates to arrangements for changing quantities,expressed as voltages proportional to said impulses expressing any ofthe said quantities in numerical form.

It is one object of the invention to provide improved apparatus forconverting analog information to digital form.

Another object is to provide a simplified but more accurate system thanheretofore available.

Still another object is to provide a device of improved reliability.

By way of brief description and according to the invention, apparatus isprovided comprising a cathode ray tube having alternately locatedelements of different secondary emission capabilities, the tubeselectron ray being deflected by means of a deflecting voltage such thatthere is produced an electric current of impulse characteristics, thenumber of impulses being proportional to the value of the deectingvoltage. Due to the above, there has been eliminated the previously usedunreliable mechanicalelectrical and electronic optical systems, and alsothere has -been obtained a substantial simplication and increase ofaccuracy. Besides, for amplification of the analog quantities amplifierscan be employed which are considerably simpler and cheaper than thosehitherto used.

The invention is disclosed in more detail in the accompanying drawing inwhich:

FIG. 1 diagrammatically shows an arrangement for changing an analogquantity into pulses;

FIG. 2 shows the pulse forms for FIG. l;

FIG. 3 shows a variation of the arrangement of FIG. l for changing a sumor a difference of two analog quantities into numerical quantities;

FIG. 4 shows a cross-section of an electronic tube which forms a vitalpart of the arrangement of the invention;

FIG. 5 shows another form of electronic tube;

FIG. 6 shows another application of an electronic tube for generating ofgroups of impulses; and

FIG. 7 shows the voltages in the arrangement of FIG. 6.

The basic element of the arrangement according to the invention is acathode ray tube provided with a conventional electron gun 1 emitting anelectron ray 2 deected by means of deecting plates 3 and also providedwith an electrode 4 consisting of the alternately placed elements 5 and6 having different values of secondary emission factors. The electronbeam hitting the electrode 4 strikes consecutively the elements 5 and 6which are included -within the deection angle 2go while in the secondarycurrent collected from the said electrode 4 there appear impulses causedby the diiierence of the secondary emission of the said elements S and6. Moreover the number of the produced impulses is equal to the numberof the elements struck by the electron beam, which means that thisnumber is strictly dependent on the deflection angle 2e, and because ofthat depends on the amplitude of the deecting voltage.

The arrangement for changing analog quantities into numericalquantities, the scheme of which is shown in FIG. 1, consists of apotential divider 7, a change-over switch 8, an integrating amplifier 9the output of which is connected with the deflecting plates 3 of thecathode ray 32,324,345 Patented .lune 6, 1967 tube, a gate generator 10,a gate system 11 and an electronic impulse counter 12.

The following is the operation of the above described arrangement.

An analog quantity converted into a voltage is applied to the input ofthe potential divider 7 and then-by closing of the change-over switchS-it is applied to the input of the integrating amplifier 9. At theinput of the said ampliiier appears an increasing or decreasing linearvariable voltage, the speed of this variation be proportional to thevalue of the analog voltage. When the variations of voltage in theintegrating amplifier are applied to the defiecting plates 3 of thecathode ray tube, they cause shifting of the electron ray with a speedproportional to the analog quantity.

The electron beam 2 moving across the electrode selects consecutive andalternately elements 5 and 6 included within the angle 2 p and becauseof thatas a result of the dierent values of the secondary emissionfactor-in the electrode 4 circuit there flows a pulsed current whereinthe number of pulses is proportional to the value of the deectingvoltage. Next the said impulses are passed to the input of the gatesystem 11, while the gate generator 10, opening the system, generates apulse of constant duration T. During the period of time when it isopened, the gate system ll'passes to the electronic counter 12 thenumber of impulses -which is proportional to the analog quantity, andthe said electronic counter counts those pulses and gives the result innumerical form.

The measurement may be carried out once or it can be repeatedperiodically, measuring each voltage in one channel or else in variouschannels by switching the required channel to the input of theintegrating amplier 9 by means of the change-over switch 8.

In FIG. 2, there are shown characteristics of the voltages at points A,B, C, D, E, F in the arrangement of FIG. 1.

Another arrangement according to the invention is shown in FIG. 3 and isused for converting a sum or a diiference of two analog quantities intonumerical quantities. This form is diierent from the above describedform in that it is provided with two potential dividers 7a and 7b eachof which is connected by means of change-over switches 8a and 8b withthe integrating amplifiers 9a and 9b, while the output of one of theseamplifiers 9a is applied to one of the deilecting plates 3a and theoutput of the second amplifier 9b is applied to the second deectingplate 3b of the impulse tube.

The analogue quantities converted into the voltages UX, and UXZ areapplied to the potential dividers 7a and 7b, and next by means of thechange-over switches 8a and Sb they are passed to the input of the twointegrating amplifiers 9a and 9b'. At the output of these integratingamplifiers 9a and 9b there are obtained two voltages increasing ordecreasing in linear manner, which voltages are next applied to the`deflecting plates 3` of the cathode ray tube for shifting the electronray the speed of which shifting is proportional to the sum or to thediiference of the analog quantities. The pulses produced by the cathoderay tube are then converted in the above described way into numericalreadings by the electronic counter 12.

In FIG. 4 there is shown an electronic tube used for producing pulsesaccording to the invention.

This electronic tube comprises the known system consisting of theelectron gdm 1 emitting an electron ray Z and the deflecting plates 3`to which there is applied the deilecting voltage from an outerelectronic system. It also comprises an electrode in the form of a bentplate 6a made of a metal of a small secondary emission factor. The metalmay be, for example, an alloy of nickel and chromium. On plate 6a thereis wound a band 5a made of a material of relatively larger value ofsecondary emission factor. This material, for example, can be berylliumbronze. The plate 6a has moreover the shape of an arc dr'awnifrom` thecenter of deflection of the electron ray 2 and is placed inside theelectron collector 13 having the form of a box made of a metal of smallsecondary emission factor. The box is fastened by means of a bracket 14to the plate 1S forming an electro-static screen separating the space inwhich is located the electrode from the space in which are placed thedefiecting plates 3. Operation of this electronic tube is the same asdescribed above.

Another form of electronic tube shown in FIG. comprises an electrodeforming a ladder consisting of small bars 16 made of metal of largesecondary emission factor, the metal being, for example, berylliumbronze. The ladder is fitted in frame 17 within an electron collectorhaving the form of a layer 18 of metal of small secondary emissionfactor for example, aluminum covering the inner surface of the tube bulb19. Operation of this form of the electronic tube differs from theoperation of the system shown in FIG. 1 in that the deflected electronbeam falls consecutively on the small bars 16 of the electrode or on thelayer 18 of the metal covering the inner surface of the bulb and havingthe smaller secondary emission factor as a result of which it producesimpulses in the current collected from the electrode. The screeningplate is in this case connected by means of springs 20 contacting theelectron collector 13.

FG. 6 shows another arrangement according to the invention, in which theabove described electronic tube is used for generating groups of pulses.

The latter arrangement consists of an electronic system 21 generating avoltage of rectangular shape and connected to the grid 22 of theelectronic tube, a system 23 generating a voltage increasing linearlyand passed to the defiecting plates 3 of the electronic tube, formingsystem 24, and amplifying system 25, which latter are connected to theelectrode 4 of the electronic tube.

The rectangularly shaped voltage, of duration T1 (FIG. 7) and ofrepetition period To, which is applied to the grid 22 and the linearvoltage from system 23, which is applied to the deflecting plates 3 ofthe electronic tube, causes pulses in the circuit of the electrode whichare passed on the output of the arrangement by the forming system 24 andthe system described above relative to FIG. 1. The defiected electronbeam falls consecutively on the small bars 16 of the electrode or on themetal layer 13` covering the inner surface of the bulb and hav ing thesmaller secondary emission factor. As a result, pulses of current areobtained from the electrode. The screening plate 15 is in this caseconnected by means of contacting springs 20` with the electron collector18.

The FIG. 3 shows another example of application o-f the arrangementaccording to the invention, in which the above described electronic tubeis used for generating groups of impulses.

The adjustment of the width of the said group of pulses obtained bysuitable adjustment of the time T1 of pulses in the system 21 and therepetition period To of these groups is adjusted by adjusting therepetition period of the pulses sent by the system 21, while the numberof impulses in each group is adjusted by adjusting the amplitude of thevoltage passed by the system 23 to the deflecting plates 3. All theabove three values can be of 4 course adjusted either incrementally orin continuous manner.

The arrangement according to the invention can 'be applied particularlyto changing analog quantities into digital and then perhaps numericalquantities but it can also be used for measuring direct-current voltageor alternatingcurrent voltage or else other physical quantities whichcan @be expressed by voltages.

What is claimed is:

1. Apparatus for the conversion of an analog signal; said apparatuscomprising a cathode ray tube including a gun adapted for generating anelectron beam, deflection plates for deecting saidbeam, and a target andcollector system including alternating elements of different secondaryemission characteristics and adapted for being swept by said beam;integrating amplifier means for receiving an input analog voltage andgenerating a linearly varying output voltage the rate of change of whichis proportional to said analog voltage, gating means coupled to thetarget and collector system to collect pulses generated in said systemwhen swept by the beam, and means coupled to said electron tube tocontrol said beam in proportion to the analog voltage to generate anumber of pulses corresponding to the analog voltage.

2. Apparatus for the conversion of an analog signal; said apparatuscomprising a cathode ray tube including a gun adapted for generating anelectron beam, deflection plates for deflecting said beam, and a targetand collector system including alternating elements of differentsecondary emission characteristics `and adapted for being swept by saidbeam; integrating amplifier means for receiving an input analog voltageand generating a linearly varying output voltage the rate of change ofwhich is proportional to said analog voltage, gating means coupled tothe target and collector system to collect pulses generated in saidsyst-em when swept by the beam, the pulses being generated at a rateproportional to the analog voltage, and gating control means coupled tothe integrating amplifier means and applying to the gating means agating signal of duration proportional to the analog voltage wherebythere is gated a number of pulses representative of the analog voltage.

3. Apparatus as claimed in claim 2, comprising a pulse counter coupledto the gating means to count the pulses.

4. Apparatus as claimed in claim 2, wherein the alternating elements areall parts of said target.

5. Apparatus as claimed in claim 2, wherein the alternating elements arerespectively parts of the target and collector.

References Cited UNITED STATES PATENTS 2,602,158 7/1952 `Carbrey 332-112,621,323 12/1952 Lesti 332--1 2,646,548 7/ 1953 Ville et al 332--112,840,637 6/1958 McNaney et al. 178--15 2,874,328 2/1959 Crost 315-122,957,104 10/ 1960 Roppel S15-8.5 2,993,201 7/1961 Roppel 340-3473,015,814 1/1962 Lippel 340-347 MAYNARD R. WILBUR, Primary Examiner.

MALCOLM A. MORRISON, Examiner.

A. L. NEWMAN, Assistant Examiner.

1. APPARATUS FOR THE CONVERSION OF AN ANALOG SIGNAL; SAID APPARATUSCOMPRISING A CATHODE RAY TUBE INCLUDING A GUN ADAPTED FOR GENERATING ANELECTRON BEAM, DEFLECTION PLATES FOR DEFLECTING SAID BEAM, AND A TARGETAND COLLECTOR SYSTEM INCLUDING ALTERNATING ELEMENTS OF DIFFERENTSECONDARY EMISSION CHARACTERISTICS AND ADAPTED FOR BEING SWEPT BY SAIDBEAM; INTEGRATING AMPLIFIER MEANS FOR RECEIVING AN INPUT ANALOG VOLTAGEAND GENERATING A LINEARLY VARYING OUTPUT VOLTAGE THE RATE OF CHANGE OFWHICH IS PROPORTIONAL TO SAID ANALOG VOLTAGE, GATING MEANS COUPLED TOTHE TARGET AND COLLECTOR SYSTEM TO COLLECT PULSES GENERATED IN SAIDSYSTEM WHEN SWEPT BY THE BEAM, AND MEANS COUPLED TO SAID ELECTRON TUBETO CONTROL SAID BEAM IN PROPORTION TO THE ANALOG VOLTAGE TO GENERATE ANUMBER OF PULSES CORRESPONDING TO THE ANALOG VOLTAGE.